Messages in this thread |  | | | Date | Mon, 10 Feb 2003 12:31:05 +0100 | | From | Andrea Arcangeli <> | | Subject | Re: stochastic fair queueing in the elevator [Re: [BENCHMARK] 2.4.20-ck3 / aa / rmap with contest] |
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On Mon, Feb 10, 2003 at 03:21:01AM -0800, Andrew Morton wrote: > Andrea Arcangeli <andrea@suse.de> wrote: > > > > On Mon, Feb 10, 2003 at 09:40:34PM +1100, Nick Piggin wrote: > > > I don't know too much about SCSI stuff, but if driver / wire / device > > > overheads were that much higher at 128K compared to 512K I would > > > think something is broken or maybe optimised badly. > > > > I guess it's also a matter of the way the harddisk can serve the I/O if > > it sees it all at the same time, not only the cpu/bus protocol after all > > minor overhead. Most certainly it's not a software mistake in linux > > that the big commands runs that much faster. Again go check the numbers > > in bigbox.html between my tree, 2.4 and 2.5 in bonnie read sequential, > > to see the difference between 128k commands and 512k commands with > > reads, these are facts. (and no writes and no seeks here) > > > > I thought scsi in 2.5 was doing 512k I/O's at present??? > > Doesn't Randy attribute the differences there to an updated > qlogic driver? (Or was the update to allow 512k I/O's? ;))
The special case of the qlogic that Randy is using does 256k commands with the new driver.
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